I propose a comprehensive programme of research on SNO+, a multi-purposeneutrino experiment that has the capacity to push forward the frontier of our knowledge in both neutrino and solar physics by addressing a wide range of physics topics. There are three main goals:A) To extend our understanding of neutrino oscillations by studying the suppression of low energy solar electron neutrino flux components.B) To address discrepancies in solar models by publishing the world's first measurement of neutrino fluxes from the CNO-cycle interactions in the Sun.And C) To contribute to the search for neutrino-less double beta decay, the so-called 'golden channel' for testing the fundamental nature of the neutrino and the absolute neutrino mass scale.The neutrino survival probabilities and CNO spectra will be extracted simultaneously in a novel approach to the solar analysis that will capitalize on theoretical correlations between the different flux components. Similar techniques will be applied to the double beta analysis allowing for a fully correlated treatment of all backgrounds and systematic uncertainties.Given the huge potential impact of these measurements, it is imperative that we maximise the physics reach of the SNO+ experiment and ensure the credibility of all results through detailed calibration and modelling to attain a complete understanding of the detector response to both the neutrino signals and inevitable background contributions. In addition to the above analysis goals, this proposal focuses on two key areas - a detailed charcterisation of the detector optical response through calibration measurements and detailed simulations and the development of an electron calibration source to confirm ourunderstanding of the detector response to electron signals across a broad energy range. Both of these unique contributions should significantly enhance the accuracy and credibility of all SNO+ physics measurements.